NATS airspace consultation

Full response to:
NATS – TERMINAL CONTROL NORTH (TCN) AIRSPACE CHANGE PROPOSALS

INTRODUCTION

The Chiltern Society is one of the largest amenity groups in England, focussed on a distinctive protected regional landscape. It has over 6,500 members. The Society’s area covers 650 square miles of the Chilterns, broadly equivalent to the area of the Chilterns Natural Character Area as defined by Natural England, and twice as large as the Chilterns Area of Outstanding Natural Beauty (AONB).

Although many of the Society’s members live outside of the Chilterns AONB, in the towns and countryside that surround it, the Society’s principal concern about NATS’ airspace change proposals has to be focussed on the protection of the AONB, which is nationally designated as representing the highest quality of English landscape and contains significant areas of internationally designated habitats. Sustaining the beauty and comparative tranquillity of the Chiltern Hills AONB is a core objective of the Society and underpins the rationale for our existence.

With the assistance of its many active volunteers, the Society conducts a wide range of activities, all of which play some part in protecting the natural and built heritage of the Chilterns and in helping many thousands of people to enjoy those valuable assets. Two of the Society’s own heritage sites and significant lengths of its 280 km. Chiltern Way circular path around the Chilterns will be directly affected by the airspace changes currently proposed by NATS.

The Society recognises that most people use air travel at some time and most people use the countryside for relaxation purposes. The Society considers that proper public policy is necessary to balance the conflicting demands of both interest groups and that NATS has failed to meet this challenge in respect of the countryside users.

As always in its planning and related matters, the Society has approached the NATS airspace consultation in what it firmly believes is a professionally objective and constructive manner.

THE SOCIETY’S RESPONSE – AN OVERVIEW

Like most other interested groups from the Chilterns, whose consultation responses we have seen, the Chiltern Society is very concerned at the potentially adverse impact on the rural Chilterns environment of the NATS proposals.

We are also surprised that, given the underlying thrust of the Government’s specific guidance to the CAA in terms of protecting AONBs and National Parks, that NATS has not adopted a more systematic and rigorous approach to adhering to that guidance than is apparent from the consultation documents. Whilst we readily accept that airspace planning is a complex multi-dimensional process, the guidance on environmental considerations and the related planning and other government guidance/policy, against which the CAA will have to assess NATS’ proposals, is clearly more demanding than NATS appears to have assumed.

We believe that CAA/DAP will be duty bound to reject the current NATS’ proposals for the TCN Chilterns and Luton area on those grounds.

We appreciate the complexity of the London airports and airspace system. However, given the substantially improved performance of the latest generation of aircraft, the improved flexibility of new navaids such as PRNAV and the strength of the guidance referred to above, the public could reasonably have expected NATS to have proposed airspace changes over the Chilterns AONB that raised, rather than lowered, the minimum altitudes of air routes over the area and to have reduced, rather than increased, the distances that aircraft fly along them at the lower altitudes permitted. That is the minimum that could reasonably be expected given the increased future volumes of air traffic likely along those routes due to the government’s estimates of air transport movement growth at London airports and the expected increases in North Atlantic traffic over the Chilterns consequent upon the EU Open Skies agreement with the US.

There has been no significant increase of the minimum altitudes of routes over the Chilterns and in several cases the distances flown by aircraft operating at the lower levels has increased. In addition, changes, such as the rerouting of westerly departures for the East and South East from Luton across the AONB to the south-west of Luton, will add very significantly to the aircraft noise burden suffered by rural communities and visitors in this part of the AONB.

We believe this is an unsatisfactory basis for future developments if air transport movements from Luton and Heathrow are to grow at the rates forecast, especially as NATS admits that its current proposals have not been planned to accommodate future airport infrastructure development beyond 2014, only 6 years away.

As for many other respondents, the Society has had some difficulty understanding the full possible implications of NATS’ proposals due to its chosen methodology for displaying the altitudes of aircraft (illustrating the “worst case”) on the route maps contained in the consultation documentation and referring to altitudes above different reference levels. NATS seems not to have fully appreciated that the Chilterns AONB rises to a height of over 850 ft. above sea level. There also seems to be a lack of coherence and consistency of approach in how NATS has weighed the environmental impact of its proposals.

The Society is grateful to NATS for attempting to answer its questions, albeit that their formal responses were not as full and helpful as we had hoped.

The Society, with the help of knowledgeable practitioners in air traffic matters, believes it has been able to identify alternative proposals that would reduce the additional aircraft noise impact on the Chilterns, compared with the NATS proposals.

We set out below an explanation of how we believe NATS has failed to follow the Government’s guidance in relation to AONBs and give a brief background as to the importance of the Chilterns AONB within a sub-regional context.

NATS claims that it has comprehensively evaluated alternative options and its resulting proposals are the most practicable, judged by the criteria it has adopted.

We consider that current-day evidence based standards really demanded a more comprehensive presentation of the option evaluations than has been made public for this current consultation process.

Finally, if indeed there are no practical alternatives to the NATS proposals for overflying the AONB, due to the complexity of the London airport and air traffic management systems, this must bring further into question whether the proposed expansion of Heathrow with a third runway and the continued expansion of Luton Airport, together with the retention of civil and military operations from Northolt, is a sustainable strategy.

IMPORTANCE OF THE CHILTERNS AONB

Areas of Outstanding Natural Beauty represent the highest quality of English landscape, a status equivalent to that of the National Parks. Both National Parks and AONBs have their origins in the same post war movements to protect the countryside and were given protective designation under the National Parks and Access to the Countryside Act 1949 to conserve and enhance their natural beauty.

Because of their fragile natural beauty the primary purpose of AONB designation is

“To conserve and enhance the natural beauty of the landscape”

Two secondary aims complement the purpose

“To meet the need for quiet enjoyment of the countryside
To have regard for the interests of those who live and work there.”
The Chiltern Hills are a major visitor attraction for people seeking peaceful, healthy outdoor recreation. Over 50 million visits are made to the Chilterns each year. This is likely to increase significantly with the increasing success of the Government’s health and access to nature agendas, particularly as the Chilterns is surrounded by major housing growth programmes.

The area has one of the densest footpath networks in the country (in excess of 2,000 miles). The Chiltern Society operates an extensive programme of volunteer led walks all across the Chilterns throughout the year. Its footpath maps are in high demand by walkers who like to plan their own walks.

Following the recent examination in public of the draft South East Plan, the panel recommended a number of policy changes to help protect the environmental quality of the Chilterns. It is also widely recognised that visitor hotspots in the Chilterns will have to meet increasing visitor demands as the populations of growth areas such as Milton Keynes and Aylesbury expand. The Forestry Commission’s Wendover Woodland Park already receives over 300,000 visitors a year. The National Trust’s Ashridge Estate is another visitor hot spot that will have to help meet the increasing demand for peaceful relaxation in the Chilterns. Both will be exposed to increased aircraft noise pollution as a consequence of the NATS proposals.

AIRSPACE PLANNING GUIDANCE

A major concern for the Society is that NATS has selectively and inappropriately interpreted Government guidance, with the result that insufficient weight has been given to minimising overflight of the AONB.

Whilst we recognise that the Government’s guidance to the CAA arguably lacks coherence and clarity, we believe the intent of that guidance, as regards AONBs, is abundantly clear and should have been more closely followed by NATS.

The guidance to the CAA’s Directorate of Airspace Policy (DAP) (Ref 2 in Appendix F of the NATS documentation) states:

“The aim is to preserve all things which make the countryside attractive and special, which includes tranquillity. The Government’s aim is to give stronger protection to the most valued landscapes in designated national parks and areas of outstanding natural beauty. Therefore, whenever practicable the DAP should:
pursue policies that will help to preserve the tranquillity of the countryside where this does not increase significantly the environmental burdens on congested areas.”

And

"Government policy will continue to focus on minimising over-flight of more densely populated areas below 7000ft. However, where it is possible to avoid over-flight of National Parks and AONBs below this altitude without adding to environmental burdens on more densely populated areas, it clearly makes sense to do so."

There is a clear implication here that DAP should seek to preserve, what appears to be, the accepted tranquillity of AONBs, provided that does not result in significant increases in the environmental burden on “more densely populated” or “congested” areas.

Whilst noting NATS’ comments on the difficulties of measuring tranquillity and the relative impact of aircraft noise, this nonetheless raises the question of what criteria NATS has used to determine what would be a “significant” increase in environmental burden over densely populated or congested areas compared to the alternative of increased environmental disbenefit to the AONB. Such criteria should take full account of the fact that more densely populated urban areas experience much higher ambient background noise levels than less densely populated countryside areas within AONBs.

NATS’ proposals to shift overflying routes into the AONB to avoid small towns such as Wendover and Princes Risborough, whilst at the same time moving other routes closer to larger Chiltern towns, such as Berkhamsted, demonstrates the lack of a coherent systematic approach to assessing the relative significance of environmental impact as required by the guidance.

The guidance does not require strict adherence to the avoidance of densely populated areas below 7000ft. Indeed it implies that there is a threshold of “environmental burden” on populated areas, below which any further reduction is insignificant enough that avoidance of National Parks and AONBs should then take precedence.

Whilst choosing to ignore the guidance about balancing the impacts on densely-populated areas and AONBs, NATS has compounded the situation by creating its own rationale for balancing impacts on densely-populated areas and fuel burn. Part B, para. 4.4. of the consultation document says:

In designing airspace, the environmental objectives relating to noise and fuel/emissions efficiency are often at odds with one another. For example a shorter route that burns less fuel may take aircraft over a town. Government guidance (Ref 2, Appendix F) does not suggest how to balance such opposing design objectives. The guidance does, however, make reference to a height threshold of 7000ft with regard to local impacts such as noise.

Despite the acknowledged absence of guidance on balancing noise and fuel burn, NATS has unilaterally introduced a threshold of 4000ft; above which reducing fuel burn has been given precedence over avoidance of populated areas.

The end result is that NATS has effectively devised a hierarchy that ignores the AONB:
• Below 4000ft: minimise overflight of densely populated areas;
• Between 4000ft and 7000ft: reducing fuel burn takes precedence.

In the Society’s view the NATS proposals are therefore fundamentally flawed by this comprehensive failure to address the Government’s guidance that seeks to protect the tranquility of the countryside and AONBs and National Parks in particular.

COMMENTS ON SPECIFIC AIRSPACE CHANGE PROPOSALS

Luton westerly departures to the south-west

We strongly believe that the Luton westerly departure route to the south-west should not be moved further south, as proposed.

The NATS consultation document states that this route was shifted south (over some of the highest open countryside within the Chilterns AONB) to avoid overflying the small Chiltern towns of Wendover and Princes Risborough at the foot of the Chiltern escarpment. Bucks County Council has denied that it supported such a change and has said that it is “wholly opposed” to these proposals. The Chiltern Society supports that view. It is questionable whether the existing noise impact on these towns is significant enough, in the terms of the guidance, to warrant changing the current route. There appears no operational reason to do so.

We consider this route should be shifted to the north, away from the Chilterns AONB, rather than to the south. This would reduce the impact on the AONB and on those towns, without significantly increasing the burden on other more populated areas or compromising air traffic control objectives.

Rerouting to the north of Wendover and Princes Risborough would seem achievable within current controlled airspace boundaries. The addition of controlled airspace to the west and south-west of Aylesbury would provide even greater flexibility for adjusting this route. Not moving the route south would also be beneficial by allowing retention of an initial climb altitude of 5,000ft.

We disagree with the NATS’ suggestion in earlier correspondence (reference SG001946-B dated 2nd May 2008) that the “guidance…to minimise the number of tracks over the ground” requires the easterly and westerly departure routes to join a common track as early as is practical in these circumstances. We presume the guidance referred to is paragraphs 30-34 of the 2002 DTLR Guidance. Paragraph 34 mentions the importance of local circumstances (and the local circumstances here are the clear environmental benefits of a more northerly route). Moreover, the example in Paragraph 33 of the guidance’s application would seem to indicate that it relates mainly to the first part of a departure route up to the point where Noise Preferential Routes cease.
We believe there is scope to restore the initial climb altitude to 5000ft, even if the route were not kept on its present alignment. (see below).

Luton easterly departures to the south-west

We understand that a defining issue here is the need to maintain separation between Luton arriving and departing traffic, and there is an essential unavoidable need to re-align the easterly departure route to the south-west for this purpose.

We believe the period for which aircraft are required to be at 4000ft could be reduced by implementing the proposal suggested below with regard to Heathrow traffic. This would bring significant benefit to, for example, the environs of Berkhamsted.

Luton westerly departures to the north, east and south-east

These are significant changes that will have an adverse impact on attractive parts of the AONB, including that part of the AONB to the north and north-east of Luton, and on significant rural visitor attractions (e.g. the National Trust’s Ashridge Estate, noted for its tranquillity). Low flying aircraft over the AONB to the south and north of Luton will be increased very significantly. Future traffic growth at Luton would exacerbate the problem.

We implore NATS to reassess the need for this change, even if that requires potential airspace structural changes that were beyond the original scope of the current exercise.

We believe, even under NATS current proposals, that there is scope to reduce the overall impact on the AONB, by requiring Luton westerly departures to the north, east and south-east to turn north as soon as possible.

We see no reason why this should not occur at or close to the point where the current Olney departure route turns north.

By extending the westerly segment of the route, as proposed by NATS, no benefit accrues to the bulk of Little Gaddesden (contrary to the implication of Para 3.3 of Section J of the consultation document), but considerable disbenefit results for the village of Marsworth and that portion of AONB between Little Gaddesden, Ivinghoe and Edlesborough.

Heathrow westerly departures to the north

A major factor influencing the level of aircraft noise exposure over the Chilterns AONB is the interaction between Heathrow and Luton air traffic. A principal constraint is the climb profile of Heathrow westerly departures to the north. Heathrow departing traffic on this routeing is itself a significant source of noise over parts of the AONB. Because Luton traffic has to remain below the minimum altitudes for Heathrow departures this has the effect of keeping the Luton traffic at lower levels over the AONB.

We understand, the low minimum altitudes for Heathrow traffic departing to the north are determined by the lowest climb performing aircraft, typically large heavy airliners heading across the North Atlantic.

We believe most of the critical low performing aircraft are older aircraft types and it is doubtful whether, for economic and competition reasons, that they will remain in service on such routes within a relatively few years.

Very significant benefits would accrue from raising the minimum altitudes of Heathrow departures on this route and we urge NATS and CAA to investigate thoroughly all practical options for achieving this and to make consequential adjustments that raise the minimum altitudes of Luton departure routes over the Chilterns.

We believe there are at least two options worthy of detailed evaluation.

1. The required climb profile of Heathrow westerly departures to the north
could be increased, so that aircraft achieve 6000ft earlier.

With improved performance of long-haul aircraft, and possibly assisted by the slower climb speed of the P-RNAV routes, we believe this is a realistic proposition.

This would enable the height profile of Luton departures to the south-west to be
raised.

We note that a current Stansted SID (DVR departure off Runway 23),
which has been in existence for some years, requires a gradient of 7.5%. It would appear therefore that this is a realistic proposal.

2. Aircraft types which cannot achieve such a more demanding climb profile (which will presumably be on transatlantic routes) should be routed initially via Compton (westwards) before joining the transatlantic route structure.

This might incur some additional route mileage and fuel consumption for a small number of aircraft. However, NATS has clearly underestimated the environmental cost of its current proposals on the Chilterns and the incremental additional fuel cost penalty of this proposal should be insignificant in net benefit terms.

Other comments

We suggest the introduction of minimum check-heights on departure routes, additional to those required by airspace and route-confliction constraints, so as to prevent aircraft choosing to stay lower than they are able to.

The consultation specifically seeks views on whether the option of “direct flightpaths” (short cuts) should be retained for inbound aircraft when traffic allows, or whether all inbound aircraft to Luton and Stansted should be required to follow defined routes via a holding stack before commencing intermediate approach. We advocate the retention of the use of direct flightpaths, on the presumption that this will help to reduce fuel burn and avoidable concentrations of aircraft noise over parts of the Chilterns AONB.

We request that the opportunity be taken during the further work suggested above to re-examine, and preferably relocate, the Bovingdon holding area, which significantly adds to the aircraft noise environment over the AONB.

CHILTERN SOCIETY

June 2008

The Chiltern Society, White Hill centre, White Hill, Chesham, Bucks, HP5 1AG. Tel: 01494 771250 Fax: 01494 793745
www.chilternsociety.org.uk